TwinCloud: A Client-Side Encryption Solution for Secure Sharing on Clouds Without Explicit Key Management

With the advent of cloud technologies, there is a growing number of easy-to-use services to store files and share them with other cloud users. Cloud service providers try to convince users to trust their services and encourage them to store personal files or corporate documents on their servers. However, both security conscious personal and cooperate users are reluctant to trust cloud service providers. Although, there are several third-party solutions to provide security in clouds, they are not used extensively because of usability issues. In this paper, we propose a novel solution, TwinCloud. TwinCloud is an innovative cloud storage solution which goal is to provide a secure cloud system to users without compromising any of the advantages the clouds have to offer. TwinCloud achieves this by solving the complex key exchange problem in sharing. It uses a simple and practical approach to store and share files by hiding all the cryptographic and key-distribution operations from cloud users. Serving as a gateway, TwinCloud uses two or more separate cloud providers and symmetric key encryption to store the encryption keys and encrypted files in separate clouds which ease the sharing process without conceding security. A usability study for TwinCloud is also included in the paper. This paper presents TwinCloud and compares it to other cloud storage systems. Keywords-cloud storage; file sharing; key management